The project would take up to four years. The Cabinet has approved $10m to get the redevelopment of Burwood Hospital underway as quickly as possible. Mr Brownlee was given a tour of the $7m, 36-bed acute medical assessment unit, which is already under construction.
He said the full project would be the "largest hospital build in the history of New Zealand's public health service" and a "very significant step" in the city's rebuild.
Mr Brownlee said the Government couldn't afford to wait to try to fund the development with a Public Private Partnership.
"... We can't spent another 12 months, two years, mucking around to see if anyone else wants to get involved ... The need is now."
Associate Health Minister Jo Goodhew, who was also due to speak but delayed along with Mr Key, said the board's facilities must be redeveloped to meet current and future needs.
"Canterbury DHB has been planning a redevelopment of its health services since 2008 but that process was interrupted by the series of destructive earthquakes in 2010 and 2011.
"The final business plan will establish the best option to build additional operating theatres, replace around 500 beds, including purpose-designed space for children, an expanded intensive care unit and emergency department at Christchurch Hospital and a new hospital for older people's health at Burwood."
Mr Brownlee said the Government would appoint a steering group of up to five people to work with the board on the final business case.
He didn't rule out candidates from outside Canterbury and promised an announcement within weeks.